The present invention generally pertains to cord-controlled apparatus for varying the disposition of a window blind, and is particularly directed to an improvement in such apparatus for controlling the disposition of the cords themselves to prevent closely gathered cords from becoming raveled.
A cord-controlled window blind apparatus, essentially includes a window blind; a set of cords coupled to the blind for raising and lowering the blind by operating the cords; a headrail from which the blind may be suspended and through which the cords extend longitudinally to separate positions where they are respectively attached to the blind. The headrail also contains an opening at which the cords are closely gathered out from which the cords extend.
A locking device is disposed in the headrail adjacent the opening for clamping the cords to hold the blind at whatever height it has been moved to by operation of the cords.
The types of window blinds that typically are controlled by such an apparatus include venetian blinds and woven wood blinds. A particularly popular type of venetian blind controlled by this type of apparatus is commonly known as "Levalors". In the cord control apparatus, two or four separate cords are used to control the raising and the lowering of the blind. These cords are gathered and extend from the opening in the headrail that is adjacent the locking device and have a tendency to become raveled.
Raveling of the cords has not been a significant problem in cord-controlled window blind apparatus having only two cords. It is when there are more than two cords that the cords become so raveled as to impair smooth operation of the apparatus.